Affiliation: | 1.V. I. Romanovskiy Institute of Mathematics of the Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan ;2.Akfa University, Tashkent, Uzbekistan ;3.National University of Uzbekistan named after Mirzo Ulugbek, Tashkent, Uzbekistan ;4.Namangam State University, Namangam, Uzbekistan ; |